At least for most of my SK flights in recent years — even when I’ve been one of less than 20 total passengers on board SK’s ORD departures — SK@ORD were open more than 3 hours before but not more than c. 4 hours before departure to take in checked luggage. I assumed that for its long-haul flights out of ORD, SK’s paying the ground handling company for c. 4 hours of staffed check-in counter service for its flight service . But with the Stockholm departure so much earlier than the Copenhagen departure, I would guess that SK is paying the contractor(s) for an equal amount of block time for each of its flights in such situation and thus it’s more than 3 hours before departure for each SK ORD departure but not more than c. 4 hours.